Telephone-exchange system.



H. P. CLAUSEN.

TELEPHONE'EXCHANGE SYSTEM.

APPLICATION FILED 050.21. 1916.

Patented Nov. 20, 1917.

2 SHEETS-SHEET H. P. CLAUSEN.

'[ELEPHONE EXCHANGE SYSTEM.

' APPUCATION FILED DEC. 21,1916- I 1 ,2465881 Patented Nov. 20, 1917.

2 SHEETS-SHEET 2.

L J l /m/e/1/0/ Henry E C/ause/v.

HENRY P. CLAUSEN', 0F MOUNT VERNON, NEW YORK,

COMPANY, INCORPORATED,

ASSIGNOR TO WESTERN ELECTRIC OF NEW YORK, N. Y., A CORPORATION OF. NEWYORK.

TELEPHONE-EXCHANGE SYSTEM.

Specification of Letters Patent.

Patented Nov. 20, 1917.

Application filed December 21, 1916. Serial No. 188,170.

To all whom it may concern.

Be it known that I, HENRY P. CLAUsEN, a citizen of the United States,residing at Mount Vernon, in the county of Wcstchester and State of NewYork, have invented certain new and useful Improvements inTelephone-Exchange Systems, of which the following is a full, clear,concise, and exact description.

This invention relates to telephone exchange systems and moreparticularly to systems of great capacity in which a connection may beestablished through the operation of an impulse transmitter.

The engineering profession has heretofore considered telephone exchangesystems utilizing automatic'switches impractical for use in large citiesor in localities Where service must be supplied to a large number of subscribers. The difliculty encountered has been, in a sense, psychologicaland due to the well-established fact that very few persons are able toaccurately remember a telephone number consisting of more than fivedigits.

The object of this invention-is to provide means whereby a very largenumber of subscribers may be served through an automatic telephoneexchange system, without the use of unreasonably long call-numbers, ormore specifically through the use of easilyremembered call-numbers.

In a system serving millions of subscribers through manually operatedexchanges any one subscriber may be called by another through the use ofa call-number which is almost in the nature of a formula, such, for'instance, as New York city, Riverside five one three four, party J,this-being due to the use of the decimal system of deslgnating telephonenumbers.

In a system embodying this invention any one of several millionsubscribers may be called through the use-of a short and easilyremembered call-number, such, for instance,

as Red, three A, B, four.

A feature of the invention is the use of other than the decimal systemin an arrangement of call-numbers and apparatus. In addition to theusual ten number digits,

other symbols such as letters of the Roman alphabet, letters of theGreek alphabet or monosyllabic words may be used as digits, anycombination ofwhich will represent a particular subscriber.

Another feature of the invention is the provision of means whereby thesubscriber in operating his impulse transmitter will not be compelled towait an unreasonable length of time between successive operations. This.may be accomplished in several ways, for

corded on a register in any well-known manner, such, for instance, asthat disclosed in the application of James L. McQuarrie, Serial No.131,455, filed November 15, 1916.

Through the use of short impulses of currents of different frequencies,the sending of impulses representing one of a large number of digitalcharacters will take the same time as the sending of any other one. Herealso the impulses may be recorded on air-egister which, in turn, willdirect the setting of the various selectors and connectors.

Through the use of the third scheme, an impulse transmitter may bearranged to send more than the usual number of trains of impulses. Allthe digital characters of a call-number exce t the last would beselected from the first ten positions, and the last only would becomposed of a greater number of impulses than ten. Thus, if tWentypositions were provided on the impulse sender and the call-numbers werelimited to four digits, the first, second, and third might be selectedin any one of ten different ways, and the fourth might be selected inany one of twenty ways, thus giving a capacity of 20,000 lines, ordouble the amount possible with the ordinary ten-position impulsesender.

Another feature of the invention is the ferred designations such as3500, pronounced three, five, hundred, and the less regularly calledsubscribers are assigned a less preferable designation, such, forinstance, as 7797, pronounced seven, seven, nine, seven.

According to this feature, the automatic switches are made responsive tothe trains of impulses representing the digits to extend a connection"from a first selector to a second selector or from a second selector toa third selector in the usual manner. They are arranged, however, to beresponsive to the trams of impulses representing the digital charactersother than the digits to extend a connection in a different manner, thatis, from a first selector to a third selector or from a second selectordirectly to a connector switch, thus eliminating a selector normallyused in the establishment of. a connection.

With the use of a designation including digital characters other thanthe digits and an arrangement of apparatus contemplated by thisinvention, a smaller number of selectors is used in setting up aconnection to a preferred subscriber, while the usual number is usedinsetting up a connection to a common subscriber. Thus the preferredsubscribers service is quickened and, therefore, enhanced in value.

-While this invention admits of the use of dial switches of anycapacity, and selector and connector switches of corresponding capacity,it may best be exemplified by the following assumptions;

A system will be described in which a twenty-position dial switch may beused. The first ten positions may be designated by the ten digits, andthe second ten may be designated by ten digital characters which may, asbefore stated, be either letters of the Roman alphabet, letters of theGreek alphabet or even short easily pronounced monosyllabic words. Theremay even be a double designation on the dials, that is, the name of anexchange may be set opposite a character so that the train of impulsesrepresenting a certain character may also represent a certain exchange.Thus we might have twenty diflerent exchange districts designated bytwenty different names, such for instance, as *Worth, Main, East, Blue,Brown or John.

It will also be assumed that the automatic selector switches shall eachbe capable of making a selection in twenty diiferent ways, that is,there shall be twenty vertical steps and a sufiicient number of rotarysteps. The connector switches may make a selection in a verticaldirection in twenty ways, and a selection in a rotary direction intwenty ways. Thus the capacity of the latter shall be four hundredlines, and the capacity of the exchange shall be a function of thenumber of selector switches used.

If it be now assumed that no telephone number shall consist of more thanfive digits, it will be seen that the system is capable of servingtwenty to the fifth power, or three million, two hundred thousandsubscribers.

It should be noted that with the decimal system used hereinbefore, theultimate ca pacity of an exchange where the call numbers are limited tofive digits has been ten to the fifth power or one hundred thousand.Thus, by an increase of one hundred per cent. in the capacity of theimpulse transmitters, an increase has been gained in the ultimatecapacity of the system of three thousand, two hundred per cent.

In the drawings, Figure l is a diagrammatic representation of thearrangement of the switching mechanisms in a large non numerical"system; Fig. 2 is a detailed representation of the same; and Fig. 3 is adetailed representation of a modification of the same arranged for adivision of service into two or more classes.

;Referring now especially to Fig. 1, the figures designated LE and soforth represent groups of line finder switches multiplied through cables1, 2, 3 and so forth, to the connector switches C C and so forth. FS SSTS represent respectively first selectors, second selectors and thirdselectors.

Each connector switch, since it must be capable of making twentyselections in both rotary and vertical movements, will have a capacityof four hundred lines, and on a ten percent. basis, C will represent abank of forty connector switches. Similarly, L'F will represent a bankof forty line finder switches.

LE to LB are banks of line finder switches constituting a major groupserving one hundred and sixty thousand subscribers lines, there beingtwenty of such major groups. They may be entered by the sending ofimpulses corresponding to twenty exchange names, though it does notfollow that they should be segregated in twenty exchange buildings. Eachmajor group then comprises four hundred such groups as LF and is in turndivided into twenty minor groups, as represented by LF to L1 in one caseand LF" to 'LF in another case, each of which minor groups in turncomprises twenty such groups as LF A subscriber having access to thesystem through the group. LF will, upon initiating a call, be served bya bank of first selectors represented by FS By then manipulating hisdial switch, the subscriber may gain access to any one of the majorgroups of one hundred and sixty thousand subscribers lines by settingthe first selector on the group of terminals leading to such majorgroup. Assluning that the first of the twenty major groups is selected.the connection may. be traced over the line 11 representing the whichthe trunks leading from FS to each of the maor groups, then over theline 12 which represents the particular group of trunks leading to thesecond selector SS of the first major group, SS to SS represent part ofthe twenty groups of second selectors into minor group is divided.

Thesecond manipulation of the subscribers dial switch results in theselection of one of twenty groups of third selectors. It will be assumedthat this selection leads to the third selectors TS, the connectiontherewith being traced over the representations of trunk cables 13 and14.

The third selection made by the subscriber extends the connectionthrough trunk cable 15 and, we will assume, through the particularconductors thereof represented by 16 to the group of connector switchesC The last two movements of the dial switch result in the extension ofthe connection within the group C to terminals of the particular linewanted.

Referring now especially to Fig. 2; LF LF", LF and LF represent banks ofline finder switches, in the same manner as LF in Fig. 1. FS, SS and TSrepresent respectively first selectors, second selectors and thirdselectors, in a manner also similar to that in Fig. 1. C C 0 and Crepresent banks of connector switches, and the line 17 represents thecable carrying the multiple conductors of lines terminating in the linefinder switches LF, and so forth, and the connector switches C and soforth.

A line entering the system in, say, line finder L15" is switched to afirst selector over one of the sets of conductors included in the cable18. If now the dial switch at the substation is manipulated in aposition designated by a digit, one of the first groups of levelsindicated will be selected, and if it is manipulated in one of thepositions designated by a character not a digit, it will be set on aline terminal in one of the upper sets of levels indichted. In eithercase the connection will be extended to the second selector. The nextset of impulses will cause one of the second selectors represented by SSto be set on the terminals of a line leading to a particular one of thegroup of third selectors represented by TS. From the third selector, anyone of the connectors represented by one of the group C to C isselected, and within this connector the particular line wanted is pickedout.

Referring. now especially to Fig. 3, this represents a modification ofthe above and shows means whereby a divided service may be renderedsubscribers.

Let it be assumed that the subscriber whose line enters the telephonesystem through the group of line finders LF is set upon one of the firstselectors FS. Let

it be further assumed that the designation of the called telephone linein this case is three, A, four, six. i

The sending of impulses representing the character 3 will thenselectively set the first selector F8 on one of the lower levels in theselector F8 thus picking out the terminals, of a second selector in thegroup represented by SS. The next series of impulses will represent thecharacter A, and the sending of these impulses will result in thesetting of the second selector on a level in the upper group of levelsindicated. The result of such a setting extends the connection past thethird selector TS", directly into one of the connector switches 0 C or CThe manipulation of the dial in the last two digital positions resultsin the selection of the particular line wanted.

If it had been assumed that a designation composed entirely of digitshad been selected, then the line entering the group of line finders LFwould, in each case, have set the selector switches on one of the firstgroup of levelsof each switch in turn, and the third selector TS wouldhave been included in such connectio Let it be assumed, as anotherexample, that a call for a prominent subscriber, or one to whompreferred service is supplied, is now initiated. Such a subscriber mighthave a telephone designation such for'instance as BF. Theaction of theline finder ELF results in the extension of the calling line to thefirst selector FS, and this first selector, in responding to the trainof im pulses representing the character B, wouldset its brushes onterminals in the upper group of levels indicated, thereby selecting anidle third selector over the trunk cable 20. An idle third selectorbeing selected, the impulses representing the character F would now besent, and would result in the setting of the brushes of TS on one of theupper levels indicated in that group. Service of this nature is to begiven only to users of a great volume, or in other words, to subscriberswhose service demands a plurality of trunks. The third selector TS beingset on one of the upper levels, will now be impelled to act in the sameway as if a connector switch were to be selected, that is, after theparticular level has been picked out, then an idle trunk in that levelmust be selected. In this case all trunks in one level lead to the samesubscriber, and the action will be the same as if an idle connectorswitch were being hunted.

What is claimed is:

1. In a telephone exchange system, lines arranged in numerical orderaccessible to calling lines by a plurality of groups of paths, less innumber than the number of lines, selector switches adapted to select apath by means of successive selections, the number of which isdetermined by the number of characters in the designation of the line towhich such path is to be established, such selectors having access tomore than ten groups of paths, whereby certain paths may be establishedby a number of selections less than the number of digits in thenumerical designation of the line to which such path extends.

2. In a telephone exchange system, lines arranged in numerical orderaccessible to calling lines by composite paths composed oi a number ofcomponent paths arranged in groups, groups of component paths individualto each character of the maximum number of characters employed torepresent such lines, groups of component paths individual to groups ofmore than one character of such maximum number, selector switchesadapted to select and interconnect successive paths in groups of eithercharacter in a single selective operation whereby a composite path maybe established to certain lines including component paths of a group ofpaths individual to a group of characters by a less number of selectiveoperations than other component paths or groups of paths individual to acharacter.

3. In a telephone exchange system, lines arranged in numerical orderaccessible to calling lines by a plurality of composite paths includingcertain component paths arranged in decimal groups and other componentpaths arranged in other non-decimal groups, less in number than suchdecimal groups, selector switches for establishing such composite pathsby successive selections depending in number upon the number of groupsof such component paths, and means in such selector switches renderingboth decimal and non-decimal groups of component paths accessibletherein, whereby certain composite paths including component paths ofthenon-decimal groups may be established by means of a less number ofselections than by composite paths including only component paths in thedecimal groups.

4. In a telephone system, lines arranged in numerical order but desiated on a nondecimal basis, said lines bemg accessible to calling linesby a plurality of groups of paths, less in number than the number oflines, selector switches arranged toselect a path by means of successiveselection, the number of which'is determined by the number of charactersin the designation of the line to which such path is to be established,such selectors having access to a plurality of groups of paths wherebycertain paths may messes be established by a number of selections lessthan the number of digits in the numerical designation of the line towhich such path extends.

5. In a telephone system, lines arranged in numerical order on anon-decimal basis, said lines being designated for purpose of calling bydigits, and characters representing numbers consisting of more than onedigit, whereby certain of said lines contain in their designation a lessnumber of characters than is necessary to distinguish them in theirnumerical order.

6. in a telephone exchange system, lines arranged in non-decimalnumerical order accessible to calling lines by compound paths composedof a number of simple paths arranged in groups, groups of simple pathsindividual to each character of the maximum number of charactersemployed to represent such lines, groups of simple paths individual togroups of more than one character of such maximum number, selectorswitches adapted to select and interconnect successive paths in groupsof either character, whereby a composite path maybe established tocertain lines including simple paths of a group of paths individual to agroup of-characters by a less number of selective operations than othersimple paths or groups of paths individual to a character.

7. In a telephone exchange system, telephone lines, means includingautomatic switches for interconnecting said lines, said switches beingresponsive to trains of impulses designated by digit to extend aconnection over a path to a switch next in order and being alsoresponsive to the trains of impulses designated by charactersrepresenting a combination of digits to extend a connection past aswitch next in order to a switch second in order. 7

8. In a telephone system, telephone lines, means including automaticswitches for interconnecting said lines, said switches being arranged inthe order of first selectors, second selectors, and so on, said switchesbeing responsive to trains of impulses designated by one group ofcharacters to extend a connection over a path leading to a selectorswitch next in order and being also responsive to trains of impulsesdesignated by another group of characters to extend a connection past aselector switch next in order to a switch second in order.

In witness whereof, I hereuntosubscribe nnnnx P. onausnn.

